Distribution transformers are often equipped with some type of internal fault detector for providing a visual indication that a fault has occurred in the transformer. For example, one commonly-used type of internal fault detector senses the temperature or pressure at one or more locations within the transformer. (A substantial increase in the operating temperature or pressure of transformer is usually indicative of a fault therein.) The internal fault detector causes some type of mechanical component, such as a pole, to extend upward from the top of the transformer when the monitored temperature or pressure exceeds a predetermined value. The extended pole functions as a visual indication that the transformer has experienced a fault.
A faulty transformer typically results in a power outage or other anomaly in the vicinity of the transformer. A repair crew from the utility company is usually dispatched to the affected area to locate and repair the faulty transformer. The repair crew visually scans the various transformers in the area until the repair crew sights the visual fault indication, i.e., the extended pole, on the faulty transformer. The faulty transformer, having thus been located, can thereafter be repaired.
The use of a visual indication to identify a faulty transformer has certain drawbacks. For example, a repair crew attempting to locate a faulty pole-mounted transformer can experience muscle strain or fatigue from repeatedly looking upward at a relatively steep angle for the fault indication. Moreover, the need to visually scan for a fault indication can distract the driver of the vehicle carrying the repair crew, thereby creating a safety hazard. Also, a visual fault indication sometimes cannot be seen from certain perspectives, especially on pole-mounted transformers.
A visual fault indication also can be difficult or impossible to see at night and under adverse weather conditions, e.g., fog or heavy rain. Furthermore, a visual indication, in general, can only be detected when the repair crew is in relatively close proximity of the transformer, i.e., when the faulty transformer is within sight of the repair crew.